Subsurface apparatus for operating well tools



Nov. 30, 1965 w. D. MYERS 3,220,480

SUBSURFACE APPARATUS FOR OPERATING WELL TOOLS Filed Feb. 6. 1961 2Sheets-Sheet 1 ITI/Go lao FI/6, 16,

WILL/mw MYERS Nov. 30, 1965 w. D. MYERS SUBSURFACE APPARATUS FOROPERATING WELL TOOLS 2 sheets-shea 2 Filed Feb. 6, 1961 lf2/6. 3a. I, 25

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INVENTOR. PWM/,QM D. MYEQS rOlQA/Ey.

United States Patent fornia Filed Feb. 6, 1961, Ser. No. 87,283 20Claims. (Cl. 166-63) The present invention relates to well boreapparatus, and more particularly to apparatus for operating tools inwell bores, such as apparatus for setting bridge plugs and packerstherewithin.

An object of the invention is to provide an apparatus adapted to belowered through casing, tubing, or similar conduit strings, ofrelatively small diameter disposed in well bores and in operating orsetting tools in such small diameter conduit strings.

Another object of the invention is to provide an improved apparatusadapted to be lowered in a well bore on a wire line and of applyingforce to a tool attached thereto sufficient to properly set or operatethe tool in the well bore.

A further object of the invention is to provide an apparatus adapted tobe lowered through fluid in a well bore and in which the hydrostatichead of the iluid is prevented from acting on the apparatus to effectits operation during lowering of the apparatus in the well bore to adesired operating point, but in which the hydrostatic head of fluid isutilized in assisting operation of the apparatus when desired.

This invention possesses many other advantages, and has other objectswhich may be made more clearly apparent from a consideration of a formin which it may be embodied. This form is shown in the drawingsaccompanying and forming part of the present specification. It will nowbe described in detail, for the purpose of illustrating the generalprinciples of the invention; but it is to be understood that suchdetailed description is not to be taken in a limiting sense, since thescope of the invention is best deiined by the appended claims.

Referring to the drawings:

FIGURES 1, 1a and lb together constitute a longitudinal section, withparts shown in side elevation, through a well apparatus in condition forlowering in a well casing, FIG. la constituting a lower continuation ofFIG. 1, and FIG. 1b constituting a lower continuation of FIG. 1a;

FIGS. 2, 2a and 2b are views corresponding to FIGS. l, la and 1billustrating the parts Vof the apparatus in another condition ofoperation, FIG. 2a, constituting a lower continuation of FIG. 2, andFIG'. 2b constituting a lower continuation of FIG. 2a.

An apparatus A is illustrated in the drawings as being lowered in a wellbore, as through a string of well casing or tubing B, on a wire line orrunning-in string C, and is shown in connection with a bridge plug Dthat is to be set within the casing, tubing, or similar well conduit B.It is to be understood, however, that the apparatus A can be used foroperating other equipment in t-he well bores than the one specificallyillustrated.

The bridge plug or well packer D is of a known type and includes a bodyhaving a guide 11 at its lower end, there being a plug 12 in the lowerend of the body for closing the passage 13 therethrough. The bridge plugincludes a set of upper segmental slips 14 releasably secured to anupper conical expander 15 by means of shear screws 16, the upperexpander being releasably secured to the body 10 by shear screws 17, orthe like. Similarly, :a lower set of slips 18 is provided, engaging thelower flange 19 of the body 10, these lower segice mental slips beingheld initially in retracted position by shear screws 20 attaching themto a lower expander 21, which, in turn, is releasably secured to thebody 10 by shear screws 22. Between the expanders 15, 21 1s a packingsleeve 23 made of rubber or rubber-like rnaterial -disposed initially inretracted position, but which is adapted to be shortened and expandedoutwardly into sealing engagement with the wall of the well casing `ortubing B upon movement of the expanders relatively toward one another.The packer body has a series of ratchet teeth 24 thereon adapted tocoact with a suitable split lock ring 25 in the upper expander 15 tohold the packer anchored against the well casing, as describedhereinbelow. As shown, the ratchet teeth 24 extend in a `downwarddirection to permit upward movement of the body 10 relative to theexpander 15, but to preclude downward movement of the body relative tothe upper expander.

In setting the bridge plug D in the well casing or tubing B, a downwardforce is imposed on the upper slips 14 and an upward force on the body10 of the tool. Such downward and upward forces are applied to thebridge plug by means of the setting or operating apparatus A securedthereto. This apparatus includes an outer cylinder 26 consisting of acylinder sleeve 27, the upper end of which is threadedly secured to anupper head or connecting sleeve 28 which is, in turn, attached to thehead 29 of a pressure chamber 30 in which a power charge 31, preferablyof relatively slow burning combustible material, is secured thatembodies its own source of oxygen. The power charge is contained withina suitable receptacle 32 resting upon the upper en-d of the head 28,there being transverse grooves 33 across the upper end of the head toallow the gases produced by combustion of the power charge t-o passaround the exterior of the receptacle 32 and through the grooves 33 tot-he passage 34 of the head for action -on parts of the apparatustherebelow, in the manner described hereinafter.

The pressure head 29 is threadedly attached to a firing head 35 suitablysecured, in a known manner, to the wire line C, which has a conductivecore (not shown) and which extends to the top of the well bore. Thecentral electrically conductive portion of the wire line makes contactwith the connector 36 within the firing head 35 mounted in an insulatingsleeve 37 therewithin and bearing against a spring 38 within the sleevewhich, in turn, bears against a ring pin 39 contacting an igniter 40clamped between the firing head 35 and the pressure head 29. Thisigniter has a filament (not shown) which becomes heated upon passage ofcurrent therethrough toA discharge the igniter, so that the flameemanating therefrom ignites the power charge 31, which will commence toburn away and generate a gas at an increasing pressure. States PatentNo. 2,640,547, to which attentionv is directed.

The `products ofv combustion are adapted to act onia' piston structure50 ydisposed within the cylinder 26 for the purpose of moving the piston50 relatively upwardly in the cylinder, and the cylinder relativelydownwardly,v

in order to set the bridge plug D or other tool connected to theapparatus A. As shown, an annular piston head Examples of power chargescan be found in United.;

sealingly engaging the wall of the sleeve. The gases under pressure passdownwardly through the piston passage 45 and then outwardly through oneor a plurality of lateral ports 46 extending through the piston belowthe piston head 41, entering the cylinder 26 below the piston head 41,and urging the latter in an upward direction. The cylinder space 47between the upper cylinder head 28 and piston head 41 and the pistontube 42 and cylinder sleeve 27 initially contains air at atmosphericpressure, and this space remains sealed so that tiuid in the well borecannot enter it. Accordingly, the gas pressure acts on the `annular areaof the piston head 41 between the periphery of the piston tube 42 andthe inner wall of the cylinder sleeve 27, urging the piston 50 in anupward direction.

The piston 50 includes an extension 48 extending from its head 4-1 andwhich may be solid. This piston extension slidably seals against a lowercylinder head 49 threadedly attached to the lower end of the cylindersleeve 27. Leakage of iiuid between the piston extension 48 and thelower cylinder head 49 is prevented by a side seal ring 51 in the headengaging the periphery of the extension 48. This extension projects intoa dashpot device 52, including an outer housing or sleeve 53 threadedlyattached to the lower cylinder sleeve or head 49, the extension beingthreadedly secured to a lower piston or mandrel 54 slidable along thewall of the dashpot housing 53. The piston extension 48 has a diametersubstantially less than the internal diameter of the housing 53,providing a cylinder space 55 therebetween and between the uppercylinder head 49 and the mandrel 54, which is filled with a suitableliquid L, such as oil, that will retard relative upward movement of thepiston S within the cylinder 26. This oil L can flow at a relativelyrestricted rate through a port 56 in the lower end of the extension 48communicating with a central passage 57 at its lower end, which, inturn, communicates with a passage 58 in the connecting mandrel 54 thathas a lateral choke port or orifice 59 extending into the dashpothousing 53 below the upper head portion 60 of the connecting mandrel 54.The head 60 of the connecting mandrel has a piston ring or side seal 61mounted therein slidably sealing against the wall of the housing 53, thelower end of the latter Aalso having a seal ring 62 engaging theperiphery of the mandrel 54 depending from its head 60 below the orice59.

Assuming the piston '50 to move upwardly in the cylinder 26, the mandrelhead 60 is also moved upwardly in the dashpot housing 53, the coniiningoil L being required to pass from the lhousing above the mandrel head 60through. the port 56 and passages 57, 58, and through the choke orifice59 into the housing 53 below the mandrel head 60. Since the orifice 59has a relatively small area, substantial time will elapse for the oil tobe transferred, thereby retarding the rate at which the piston 50 canmove upwardly in the cylinder 26.

The lower end of the connecting mandrel 54 is threadedly attached to ahydrostatic head piston or booster piston 65, which is threadedlyattached t0 the upper end of a tubular tension body 66 extendingdownwardly from the piston within an encircling setting sleeve 67, theupper end of which is threadedly attached to the dashpot housing 53, andthe lower end of which is attached to a sleeve extension 68 engageablewith the upper set of segmental slips 14 of the bridge plug D. Thetension body 66 is threadedly secured to a rod 69 connected to a sleeve70 threaded into the upper end of the packer body 10. The connectionbetween the rod 69 and sleeve 70 is Y a transverse -shear pin 71 adaptedto be disrupted when a 'suiiicient force is imposed therewithin. Thispin has a substantially greater shear strength than the total forcedesired to expand the slips 14, 18 against the well casing or tubing Band the packing sleeve 23 against the casing or tubing B, so that thepin 71 is sheared only after the bridge plug D has been anchored inpacked-off condition against the well casing for the purpose of thenreleasing the setting apparatus A from the bridge plug D.

During lowering of the apparatus through fluid in the tubing or casingstring B, the hydrostatic head of iiuid. can act in an upward directionon the booster piston 65 and might tend to prematurely set the bridgeplug A in the well casing. To preclude this action from happening, thehydrostatic head of uid is, at iirst, prevented"l from acting on thebooster piston 65 over a differential area of the latter. Inaccomplishing this purpose, ther lower portion 72 of the booster pistonis of a reduced diameter and is piloted within a lock sleeve 73 havingas comparatively heavy cap screw or holding element 74 threaded in itssolid lower end and extending through a; longitudinal slot 75 in thetension body and into an opening or recess 76 in the setting sleeve 67.The lower portion 72 of the booster piston has a suitable side sealringl 77 engaging the inner wall ofthe lock sleeve 73. Sincel the lowerend 73a of the lock sleeve 73 is solid, the lock sleeve chamber 78initially contains air at atmospheric pressure below the booster piston72. The hydrostatic head of fluid can then only engage the boosterpiston 65 and tend to urge the latter in an upward direction over anarea between the inner surface 79 of the lock sleeve 73 and the innersurface 80 of the setting sleeve 67. However, the same hydrostatic headof fluid can flow upwardly through the clearing space around the tensionbody 66 and into the setting sleeve 67 above the booster piston 65. Thediameter of the mandrel 54 below the dashpot housing 53 may be madesubstantially equal to the internal diameter of the lock sleeve 73. As aresult, the hydrostatic head of iiuid is acting in a downward directionon the booster piston 65 over substantially the same area as it isacting in an upward direction over the booster piston. Accordingly, thehydrostatic head of fluid will not tend to urge the booster piston 65,mandrel 54 and the piston 50 in the cylinder 26 in an upward direction,and cannot, therefore, urge the tension body 66, rod 69 and the packertbody 1) in an upward direction, which might prematurely trip or set thebridge plug D during lowering of the apparatus through the fluid .in thetubular string.

However, once the setting point in the well bore is reached and thepower charge 31 ignited to generate fluidil pressure, the piston 50 ismoved upwardly in the cylinder' 26, carrying the mandrel 54 and thebooster piston 65 upwardly with it, the seal ring 77 on the pistonmoving upwardly out of the lock sleeve 73, thereby exposing the centralarea of the booster piston 72 to the action of the hydrostatic head offluid, which will then assist in shifting the piston 65 and mandrel S4in an upward direction, the hydrostatic head adding its setting force tothe force of the gas generated within they cylinder 26 and actingupwardly on the piston 50.

The apparatus is run in the well bore, with its parts in the positionillustrated in FIGS. 1, 1a and b, the parts of the bridge plug D beingin their initial retracted positions, with the shear pin 71 attachingthe setting apparatus A to the bridge plug. At this time, the mandrelhead 60 is in a lower position within the dashpot housing 53 and thepiston head 41 is in a lower position within its cylinder 26.

After the apparatus has been lowered in the well conduit B on the wireline C to the position at which the bridge plug D is to be anchored inthe tubular string, a suitable current is sent down the wire line todischarge the igniter 40, the ame issuing therefrom acting upon theupper end of the power charge 31 and commencing its burning. The gasesevolving from the power charge will then pass downwardly around thecharge holder 32, flowing through the grooves 33 to the interior passage34 of the cylinder head 28, and then through the hollow or tubularpiston extension 42 and through the ports 46 into the cylinder 26 belowthe piston head 41. The piston head then moves upwardly within thecylinder 26, or the cylinder moves relatively downwardly along thepiston head 41, the relative upward movement being transmitted from thepiston 50 to the mandrel 54, tubular body 66, rod 69 and shear pin 71 tothe sleeve 70 and the body of the packer D, urging the body 10 in anupward direction. At the same time, the gas pressure is acting in adownward direction on the lower cylinder head 49, urging the cylinder 26and the dashpot housing 53 and the setting sleeve 67, 68 in a downwarddirection against the upper slips 14. When the pressure in the cylinder26 reaches a value that exceeds the corresponding shear strength of t-hescrews 16 holding the upper slips 14 to the upper expander 15, suchscrews are disrupted (since the screws 17 holding the upper expander 15to the body 10 are stronger, which is also true of the screws 22, 20holding the lower expander 21 andslips 18 in retracted position). Theslips 14 are shifted by the sleeve 68 relatively downwardly along theupper expander 15 and outwardly into engagement with the well casing. Atthis time, the piston 50 will have relatively lifted the booster piston65 at the lower end of the mandrel 54 out of the lock sleeve 73 so thatthe force acting upwardly on the piston head 41 is supplemented by theforce attributable to the hydrostatic head of uid acting in an upwarddirection over the central area of the booster piston 65.

The piston 50 and mandrel 54 will continue to exert an upward force onthe packer body 10, and when such force exceeds the strength of theshear screws 17 holding the upper expander 15 to the body 10, the screwsare disrupted, whereupon the lower expander 21 is moved towards theupper expander 15, shortening the packing sleeve 23 and expanding itoutwardly into sealing engagement with the wall of the well casing B andalso urging it inwardly against the periphery of the packer body 10. Therelative upward motion of the piston 50, mandrel 54 and packer body 10continues until the shear strength of the screws 20 holding the lowerslips 1S to the lower expander 21 and the lower expander to the body 10are exceeded, such screws disrupting and the lower slips 18 then beingshifted upwardly along the lower expander 21 and outwardly intoengagement with the wall casings (FIGS. 2, 2a, 2b). As the pressure inthe cylinder 26 continues to increase, due to the continued generationof gas resulting from burning of the power charge 31, the cylinder 26and piston 50 are moved relatively in opposite directions to expand theslips 14, 18 into firmer anchoring engagement with the wall of the wellcasing B, and the packing sleeve 23 into firmer sealing engagement withthe well casing or tubing B and the body 410 of the packer D.

The pressure in the cylinder 26 will continue to increase until theshear strength of the pin 71 is exceeded, whereupon the latter isdisrupted to release the setting apparatus A from the bridge plug D. Thesetting ap. paratus A can now be elevated by means of the wire line Cthrough the tubing or casing B and removed `completely therefrom,leaving the bridge plug D anchored in packed-oft" condition in thetubular string B.

For the piston 50 and mandrel structure 54 attached thereto to moverelatively upwardly in the cylinder 26 and housing 53, in accomplishingthe setting of the bridge plug D and release of the apparatus A from thebridge plug, in the manner described, it is necessary for the oil L inthe housing 53 to be displaced from the upper side of the mandrel heador piston 60 to its lower side. Because of the restricted area of theorice 59, such dis-l placement can only occur at a relatively slow rate.Thus, the oil L must pass from the upper side of the mandrel head 60,through the passages 56, 57, 58, and through the orifice 59 to its lowerside. As the several shear screws are disrupted, sudden expansion of thegas in the cylinder 26 is prevented, because of the retarding action ofthe oil L passing through the orifice 59. Similarly, the suddenrelieving of the apparatus A of load, resulting from disruption of theshear pin 71 that disconnects the apparatus from the bridge plug D, doesnot impose any impact or shock loads on the system, since the piston 50can only move relatively in the cylinder 26 at a comparatively slowrate, because of the necessity for the transfer of oil L from one sideof the mandrel head 60 to its other side through the relatively `smallorifice 59. Accordingly, the piston 50 cannot suddenly be shifted intohammering engagement with the upper cylinder head 2S, being broughtrelatively gradually upwardly within the cylinder 26, until it engagesthe head 28.

By virtue of the apparatus described, a Substantial setting force isprovided for firmly anchoring the bridge plug D in packed-off conditionin the well casing or tubing B. The hydrostatic head of fluid isineffective in inadvertently and prematurely setting the bridge plugduring its lowering through uid in the tubular string B, but suchhydrostatic head of uid is still availed of to supplement the forceimposed by the evolved gases on the lower side of the piston head 41within the cylinder 26. The piston 50 is not required to overcomehydrostatic head of fluid in the well casing B, since its low pressureside is only subject to air at atmospheric pressure in the cylinder 26,which pressure will only increase to a comparatively small andinsignificant degree upon compression of the air in the cylinder,resulting from upward movement of the piston 50 therewithin. If desired,the area of the booster piston 65 subject to the hydrostatic head duringlowering of the apparatus through liquid in the tubing B may be madeslightly greater on its upper side than on its underside, so that thereis a slight area differential on which the hydrostatic head of fluidwill act and tend to hold the mandrel 54 and the piston 50 in a downwarddirection in the cylinder 26, as positive assurance against prematuretripping or setting of the bridge plug D. The provision of the dashpot52 and the manner in which it is provided in the apparatus insuresagainst sudden shock loads being imposed on the apparatus, by precludingimpacting between the several parts.

I claim:

1. In apparatus for operating a well device in a well bore: a cylinderadapted to be connected to a running-in string for lowering theapparatus in the well bore; a hollow piston moveable in said cylinderand including an actuating piston head and a rod portion extending fromsaid head, said piston having a passage from its interior to thecylinder on the high pressure side of said head; said head and rodportion being in iluid tight engagement with said cylinder to provide aclosed fluid tight space on the low pressure side of said head;releasable means preventing said piston from moving in said cylinderduring lowering of said apparatus in the well bore; and means in said:cylinder providing a iiuid under pressure adapted to pass through saidhollow piston and passage into the cylinder for moving said pistonrelatively in said cylinder.

2. In apparatus for operating a well device in a well bore: a cylinderadapted to be connected to a running-in string for lowering theapparatus in the well bore; a hollow piston movable upwardly in saidcylinder and including a lower piston head and a rod portion extendingupwardly from said head, said piston having a passage from its interiorto the cylinder below said head; said head and rod portion being influid tight engagement with said cylinder to provide a closed fluidtight space above saidV head; said piston having a lower portionextending downwardly from said cylinder; means initially preventing thehydrostatic head of fluid from acting on said lower portion; and meansin said cylinder above said piston providing a duid under pressureadapted to pass through said hollow piston and passage into saidcylinder for moving said piston relatively upwardly in said cylinder andto shift said lower portion from said preventing means to a position inwhich the hydrostatic head of fluid can act upon said lower portion andurge said piston upwardly in said cylinder.

3. In apparatus for operating a well device in a well bore: a cylinderadapted to be connected to a running-in string for lowering theapparatus in the well bore and including spaced upper and lower headsand a sleeve between and secured to said heads, a piston in saidcylinder including a head slidable along said sleeve, an upper rodportion slidable in said upper cylinder head, and a lower rod portionslidable in said `lower cylinder head and adapted to be subject to thehydrostatic head of fluid in the well bore tending to shift said pistonupwardly in said cylinder, said piston having a passage thereinextending from the upper end of said upper rod portion to said cylinderbetween said piston head `and lower cylinder head; said pis-ton head andupper rod portion being in uid tight engagement with said lcylindersleeve and upper cylinder head, respectively, to provide -a closed tiuidtight space between said piston and cylinder above said piston head;means initially preventing the hydrostatic head of uid from acting onsaid lower rod portion; and means in said cylinder above said pistonproviding a fluid under pressure adapted to pass through said passageinto said cylinder for moving said piston relatively upwardly in saidcylinder and to shift said lower rod portion from said preventing meansto a position in which the hydrostatic head of fluid can act upon saidlower rod portion and urge said piston upwardly of said cylinder.

4. In apparatus for operating a well device in a well bore: a cylinderadapted to be connected to a running-in string for lowering theapparatus in the well bore; a hollow piston movable in said cylinder andincluding an actuating piston head and a first rod portion extending inone direction from said head, said piston having a passage from itsinterior to the cylinder on the high pressure side of said head; saidhead and first rod portion being in uid tight engagement with saidcylinder to provide a closed fluid tight space on the low pressure sideof said head; means in said cylinder providing a iiuid under pressureadapted to pass through said hollow piston and passage into the cylinderfor moving said piston relatively in said cylinder; a housing secured tosaid cylinder; said piston having a second rod portion extending in theopposite direction from said actuating head into said housing; aretarding piston head secured to said second rod portion and slidable insaid housing; said housing being adapted to contain a liquid on one sideof said retarding piston head; means providing a restricted passage fromsaid housing on said one side of said retardng piston head to the otherside thereof through which the liquid is forced by said retarding pistonhead during movement of said piston in said cylinder; a third rodportion secured to said retarding piston head and extending outwardly ofin fluid tight relation to said housing, said third rod portion beingadapted to be subject to the hydrostatic head of fluid in the well bore;means initially preventing the hydrostatic head of fluid from acting onsaid third rod portion; said third rod portion being shifted from saidpreventing means, upon movement of said piston in said cylinder, to aposition in which the hydrostatic head of iiuid can act upon said thirdrod portion.

5. In apparatus for operating a well device in a well bore: a cylinderadapted to be connected to a running-in string for lowering theapparatus in the well bore; a hollow piston movable upwardly in saidcylinder and including an actuating piston head and an upper rod portionextending upwardly from said head, said piston having a passage from itsinterior to the cylinder below said head; said head and upper rodportion being in tluid tight engagement with said cylinder to provide aclosed iiuid tight space above said head; means in said cylinder abovesaid piston providing a iluid under pressure adapted to pass throughsaid hollow piston and passage into said cylinder for moving said pistonrelatively upwardly in said cylinder; a housing below and secured tosaid cylinder; said piston having a lower rod portion extending fromsaid actuating head into said housing; a retarding piston head securedto said lower rod portion and slidable in said housing; said housingbeing adapted to contain a liquid above said retarding piston head;means providing a restricted passage from said housing above saidretardingk piston head to a region below said retarding piston headthrough which the liquid is forced by said retarding piston head duringrelative upward movement of said piston in said cylinder; a third rodportion secured to said re- 10 tarding piston head and extendingoutwardly of in iluid tight relation to said housing, said third rodportion being adapted to be subject to the hydrostatic head of fluid inthe well bore; means initially preventing the hydrostatic head of uidfrom acting on said third rod portion; said third rod portion beingshifted from said preventing means, upon movement of said piston in saidcylinder, to a position in which the hydrostatic head of uid can actupon said third rod portion.

6. In apparatus for operating a well device in a well bore: a cylinderadapted to be connected to a running-in string for lowering theapparatus in the well bore and including spaced upper and lower headsand a sleeve between and secured to said heads; a piston in saidcylinder including a head slidable along said sleeve, an upper rodportion slidable in said upper cylinder head, and a lower rod portionslidable in said lower cylinder head, said piston having a passagetherein extending from the upper end of said upper rod portion to saidcylinder between said piston head and lower cylinder head; said pistonhead and upper rod portion being in uid tight engagement with saidcylinder sleeve and upper cylinder head, respectively, to provide aclosed uid tight space between said piston and cylinder above saidpiston head; means in said cylinder above said piston providing a uidunder pressure adapted to pass through said passage into said cylinderfor moving said piston relatively upwardly in said cylinder; a housingbelow and secured to said lower cylinder head and into which said lowerrod portion extends; a retarding piston head secured to said lower rodportion and slidable in said housing; said housing being adapted tocontain a liquid above said reta-rding piston head; means providing arestricted passage from said housing above said retarding piston head toa region below said retarding piston head through which the liquid isforced by said retarding piston head during relative.

upward movement of said piston in said cylinder; a third rod portionsecured to said retarding piston head and extending outwardly of iniluid tight relation to said housing, said third rod portion beingadapted to be subject to the hydrostatic head of fluid in the well bore;

means initially preventing the hydrostatic head of uid from acting onsaid third rod portion; said third rod portion being shifted from saidpreventing means, upon movement of said piston in said cylinder, to aposition in which the hydrostatic head of fluid can act upon said thirdrod portion.

7. In apparatus for operating a well device in a well bore: a cylinder;means on said cylinder thor `connecting said cylinder to a running-instring for lowering the apparatus in the well bore; a hollow pistonmovable in said cylinder and including an actuating piston head and arod portion extending from said head, said piston having a passage fromits interior to the cylinder on thev high pressure side of said head;said head and rod portion being in iluid tight engagement with saidcylinder to said cylinder.

8. In apparatus for operating a well device in a well bore: a cylinder;means on said cylinder for connecting said cylinder to a running-instring for lowering the apparatus in the well bore; a hollow pistonmovable in said cylinder and including an actuating piston head and arod portion extending from said head, said piston having a passage fromits interior to the cylinder on the high pressure side of said head;said head and rod portion being in fluid tight engagement with saidcylinder to provide a closed fluid tight space on the low pressure sideof said head; and means including means passing into said hollow pistonand passage providing fluid under pressure in said cylinder on the highpressure side of said head to move said piston relatively in saidcylinder.

9. In apparatus for operating a well device in a well bore: a cylinder;means on said cylinder for connecting said cylinder to a running-inlstring for lowering the apparatus in the well bore; a hollow pistonmovable upwardly in said cylinder and including a lower piston head anda rod portion extending upwardly from said head, said piston having apassage from its interior to the ycylinder below said head; said headand rod portion being in fluid tight engagement with said cylinder toprovide a closed lluid tight space above said head; and means above saidpiston for directing iluid under pressure into said hollow piston andpassage whereby said fluid under pressure moves said piston .relativelyupwardly in said cylinder.

10. In apparatus for operating a well device in a well bore: a cylinder;means on said cylinder for connecting said cylinder to a running-instring for lowering the apparatus in the well bore; a hollow pistonmovable upwardly in said cylinder and including a lower piston head anda rod portion extending upwardly from said head, said piston having apassage from its interior to the cylinder below said head; said head androd portion being in fluid tight engagement with said cylinder toprovide a closed uid tight space above said head; means providing fluidunder pressure in said cylinder on the high pressure side of said headto move said piston relatively upwardly in said cylinder, said meansincluding instrumentalities above said piston adapted to pass downwardlythrough said hollow piston and passage.

11. In apparatus for operating a well device in a well bore: a cylinder;means on said cylinder for connecting said cylinder to a running-instring for lowering the apparatus in the well bore and including spacedupper and lower heads and a sleeve between and secured to said heads; apiston in said cylinder including a head slidable along said sleeve, anupper rod portion slidable in said upper cylinder head, and a lower rodportion slidable in said lower cylinder head, said piston having apassage therein extending from the upper end of said upper rod portionto said cylinder between said piston head and lower cylinder head; saidpiston head and upper rod portion being in uid tight engagement withsaid cylinder sleeve and upper cylinder head, respectively, to provide aclosed fluid tight space between said piston and cylinder above saidpiston head; and means above said piston for directing fluid underpressure into said hollow piston and passage whereby said liuid underpressure moves said piston relatively upwardly in said cylinder.

12. In apparatus for operating a well device in a well bore: a cylinder;piston means movable in said cylinder when subjected to fluid underpressure; said piston means including a member extending out of saidcylinder and adapted to be subjected to the hydrostatic head of fluid inthe well bore; means disposed in sealed relation to said memberexternally of said cylinder preventing the hydrostatic head of fluidfrom acting on said member; and means for directing fluid under pressureto said piston means to relatively move said piston means in saidcylinder and to move said member with respect to said preventing meansfrom sealed relation thereto to a position in which the hydrostatic headof fluid can act on said member.

13. In apparatus for operating a well device in a Well bore: a cylinder;piston means movable in said cylinder when subjected to fluid underpressure; said piston means including a member extending out of saidcylinder and adapted to be subjected to the hydrostatic head of fluid inthe well bore; means encompassing said member in sealed relation theretoexternally of said cylinder to prevent the hydrostatic head of lluidfrom acting on said member; and means for directing uid under pressureto said piston means to relatively move ysaid piston means in saidcylinder and to remove said member from said encompassing means wherebythe hydrostatic head of fluid can act on said member.

14. In apparatus for operating a well device in a well bore: a cylinder;piston means movable relatively in one direction in said lcylinder whensubjected to fluid under pressure; said piston means including a memberextending out of said cylinder and adapted to be subjected to thehydrostatic head of fluid in the well bore and tending t0 move saidpiston means in said one direction; means disposed in sealed relation tosaid member externally of said cylinder preventing the hydrostatic headof iluid from acting on said member; and means for directing fluid underpressure to said piston means to relatively move said piston means insaid cylinder and to move said member with respect to said preventingmeans from sealed relation thereto to a position in which thehydrostatic head offluid can act on said member.

15. In apparatus for operating a well device in a well bore: a cylinder;piston means movable relatively in one direction in said cylinder whensubjected to fluid under pressure; said piston means including a portionextending out of said cylinder and adapted to be subjected to thehydrostatic head of fluid in the well bore and tending to move saidpiston means in said one direction; means encompassing said portion insealed relation to said portion externally of said cylinder to preventthe lhydrostatc head of fluid from acting on said portion; and means fordirecting uid under pressure to said piston means to relatively movesaid piston means in said cylinder and to remove said portion from saidencompassing means whereby the hydrostatic head of fluid can act on saidportion.

16. In apparatus for operating a well device in a well bore: a cylinder;piston means movable relatively upwardly in said cylinder when subjectedto fluid under pressure; said piston means including a portion extendoutof said cylinder and adapted to be subjected to the hydrostatic head offluid in the well bore and tending to move said piston means relativelyupwardly in said cylinder; means disposed in sealed relation to said.portion externally of said cylinder preventing the hydrostatic head offluid from acting on said portion; and means for directing fluid underpressure to said piston means to relatively move said piston meansupwardly in said cylinder and to move said portion with respect to saidpreventing means from sealed relation thereto to a position in which thehydrostatic head of uid can act on said portion.

17. In apparatus for operating a well device in a well bore: a cylinder;piston means movable relatively upwardly in said cylinder when subjectedto fluid under pressure; said piston means including a portion extendingout of said cylinder and adapted to be subjected to the hydrostatic headof fluid in the well bore and tending to move said piston meansrelatively upwardly in said cylinder; means encompassing said portion insealed relation thereto externally of said cylinder to prevent thehydrostatic head of fluid from acting on said portion; and means fordirecting fluid under pressure to said piston means to relatively movesaid piston means upwardly in said cylinder and to remove said portionfrom said encompassing means whereby the hydrostatic head of fluid canact on said portion.

18. In apparatus for operatng a well device in a well bore: a cylinderadapted to be connected to a runningin string for lowering the apparatusin the well bore and including spaced upper and lower heads and a sleevebetween and secured to said heads; a piston in said cylinder including ahead slidable along said sleeve, an upper rod portion sildable in saidupper cylinder head, and a lower rod portion slidable in said lowercylinder head, said piston having a passage therein extending from theupper end of said upper rod portion to said cylinder between said pistonhead and lower cylinder head; said piston head and upper rod portionbeing in fluid tight engagement with said cylinder sleeve and uppercylinder head, respectively, to provide a closed iuid tight spacebetween said piston and cylinder above said piston head; said lower rodportion being adapted to be subjected to the hydrostatic head of Huid inthe well bore tending to move said piston relatively upwardly in saidcylinder; means encompassing said lower rod portion in sealed relationthereto to prevent the hydrostatic head of lluid from acting thereon;and means in said cylinder above said piston providing a liuid underpressure adapted to pass through said passage into said cylinder formoving said piston relatively upwardly in said cylinder and to removesaid lower rod portion from said encompassing means whereby thehydrostatic head of fluid can act on said portion.

19. In apparatus for operating a well device in a well bore: a cylinderadapted to be connected to a running-in string for lowering theapparatus in the well bore and including spaced upper and lower headsand a sleeve between and secured to said heads; a piston in Saidcylinder including a head slidable along said sleeve, an upper rodportion slidable in said upper cylinder head, and a lower rod portionslidable in said lower cylinder head, said piston having a passagetherein extending from the upper end of said upper rod portion to saidcylinder between said piston head and lower cylinder head; said pistonhead and upper rod portion being in iluid tight engagement with saidcylinder sleeve and upper cylinder head, respectively, to provide aclosed fluid tight space between said piston and cylinder above saidpiston head; said lower rod portion being adapted to be subjected to thehydrostatic head of Huid in the well bore tending to move said pistonrelatively upwardly in said cylinder; means connected to said cylinderand encompassing said lower rod portion in sealed relation thereto toprevent the hydrostatic head of iluid from acting on said lower rodportion; and means in said lcylinder above said piston providing a lluidunder pressure adapted to pass through said passage int-o said cylinderfor moving said piston relatively upwardly in said cylinder and toremove said lower rod portion from said encompassing means whereby thehydrostatic head of fluid can act on said lower rod portion.

20. In apparatus for operating a well device in a well bore: a cylinderadapted to be connected to a runningin string for lowering the apparatusin the well bore and including spaced upper and lower heads and a sleevebetween and secured to said heads; a .piston in said cylinder includ-inga he-ad slidable along said sleeve, an upper rod portion slidable insaid upper cylinder head, and a lower rod portion slidable in said lowercylinder head, `said piston lhaving a passa-ge therein extending fromthe upper end of said upper rod portion to said cylinder between saidpiston head and lower cylinder head; said piston head and upper rodportion being in fluid tight engagement with said cylinder sleeve andupper cylinder head, respectively, to provide a closed fluid tight spacebetween said piston and cylinder above said piston head; said lower rodportion being adapted to be subjected to the hydrostatic head of fluidin the well bore tending to move said piston relatively upwardly in saidcylinder; a sleeve receiving said lower rod portion in leak-proofrelation and being closed below said lower rod portion to prevent t-hehydrostatic head of uid from acting on said lower rod portion; meansattaching said sleeve to said cylinder; and means in said cylinder abovesaid piston providing a fluid under pressure adapted to pass throughsaid passage into said cylinder for moving said piston relativelyupwardly in said cylinder and to remove said lower rod portion from saidsleeve whereby the hydrostatic head of fluid can act on said lower rodportion.

References Cited by the Examiner UNITED STATES PATENTS 1,747,398 2/1930Short 166-63 2,279,676 4/1942 Hart 166-63 2,308,004 1/1953 Hart 166-632,326,404 8/1943 Spangler 166-63 2,537,413 1/1952 Lawrence 166-982,595,014 4/1952 Smith et al 166-98 2,692,023 10/1954 Conrad 166-632,807,325 9/1957 Webb 166-63 2,829,716 4/1958' Stewart 166-98 2,978,0284/1961 Webb 166--63 3,029,873 4/1962 Hanes l66-l35 X 3,079,997 3/1963Blydorp 166-135 X 3,160,209l 12/1964 Bonner 166-63 CHARLES E. OCONNELL,Primary Examiner.

BENJAMIN BENDETT, Examiner.

7. IN APPARATUS FOR OPERATING A WELL DEVICE IN A WELL BORE: A CYLINDER;MEANS ON SAID CYLINDER FOR CONNECTING SAID CYLINDER TO A RUNNING-INSTRING FOR LOWERING THE APPARATUS IN THE WELL BORE; A HOLLOW PISTONMOVABLE IN SAID CYLINDER AND INCLUDING AN ACTUATING PISTON HEAD AND AROD PORTION EXTENDING FROM SAID HEAD, SAID PISTON HAVING A PASSAGE FROMITS INTERIOR TO THE CYLINDER ON THE HIGH PRESSURE SIDE OF SAID HEAD;SAID HEAD AND ROD PORTION BEING IN FLUID TIGHT ENGAGEMENT WITH SAIDCYLINDER TO PROVIDE A CLOSED FLUID TIGHT SPACE ON THE LOW PRESSURE SIDEOF SAID HEAD; AND MEANS FOR DIRECTING FLUID UNDER PRESSURE INTO SAIDHOLLOW PISTON AND PASSAGE WHEREBY SAID FLUID UNDER PRESSURE MOVES SAIDPISTON RELATIVELY IN SAID CYLINDER.